Using the polymer-network gel method to control the chemical procedure, Sr2FeMoO6 powders with grain size of 50 nm (A) and 100 nm (B) have been synthesized, and their structural and electrical properties have been investigated. By comparing the experimental results of samples A and B with that of bulk sample C with grain size in mu m obtained before, sample A shows the largest bulk modulus B (0) and a relatively large slope of the drop in resistance as a function of pressure. The possible reasons are given and discussed.